A typical electroluminescent display comprises an array of electroluminescent elements arranged in rows and columns in which the anodes of the electroluminescent elements on each row are electrically connected to one of a plurality of anode lines and the cathodes of the electroluminescent elements on each column are electrically connected to one of a plurality of cathode lines, and a driving system to switch the anode lines and the cathode lines between two phases according to display data for specifically lighting up one or ones of the electroluminescent elements.
To speed up the electroluminescent elements in an electroluminescent display to light up, the driving system disclosed by U.S. Pat. No. 5,844,368 to Okuda et al. precharges the electroluminescent element that is to be lighted up. In this driving scheme, however, all the anodes and cathodes of the electroluminescent elements are grounded for the electric charges thereon to be completely discharged before an electroluminescent element is lighted up and as a result, each time the electroluminescent element is charged from 0 V when it is to be lighted up, which requires greater power consumption. Furthermore, the current supplied to the electroluminescent elements by the current source of the driving system is so small that the electroluminescent display slowly responds to the driving control.
On the other hand, the driving system proposed by U.S. Pat. No. 6,501,226 to Lai et al. comprises switches each of which is inserted between two adjoining cathode lines of the electroluminescent element array, and turns on the corresponding one or ones of the switches between the cathode line being scanned and the next cathode line to be scanned to equalize the electric charges in the electroluminescent elements on the currently scanned cathode line and on the next cathode line to be scanned, so as to reduce the power demand of lighting up the electroluminescent elements.
There is still a need of reduced power demand and enhanced performance in response speed for an electroluminescent display.